Com Ed Outrageous Charges Internet, Illinois

I recently moved within Chicago and am receiving ComEd bills at approx $300 a month. It appears to be an ESTIMATED bill, though their website does not explain that in their "Understanding Your Bill" and I cannot understand how it could be so much when I haven't changed my lifestyle from the previous place which I paid at most $90 a month...and I have GAS heat on top of it. One significant difference I noticed in the invoices is the "Distribution Facilities Charge." Apparently it means (according to ComEd)  kW (kilowatts) X MKD (Maximum Kilowatts Delivered) for the billing period. My previous bills stated the cost to be $12.95 and now they are at $58.23. Does anyone know what this may pertain to?  I have already contacted ComEd to look into it and they have found no errors.